I seem to recall looking up this item found in the boot of a Jaguar from the wreckers, maybe called a Lucas voltage sports coil.
what does it do (ok, it amplifies volts) for what purpose and what use could one make of it (paper weight?)

 

Its an Ignition Coil.

Usually bolted to the side of the engine, close by the distributor (mostly), and if its Lucas brand, a paper weight makes a good alternative use, and probably significantly more reliable doing that, as compared to what it was originally design to do.

It provides the High Voltage spark for the spark plugs, which in turn ignites the fuel/air mixture and gives birth to the internal combustion engine.

Not sure of the "Sports" connotation, being Lucas and all that.